RESUMO

Industrial wastewater and agricultural practices are among the main activities discharging organic pollutants, such as Polychlorinated biphenyl (PCB) congeners and organochlorine insecticides (e.g. DDT - dichloro diphenyl trichloroethane), to the environment. In this study, we used the native Cichlidae fish species Geophagus brasiliensis as a sentinel to evaluate the hepatic 7-ethoxyresorufin-O-deethylase EROD activity, a biomarker of exposure to CYP1A-inducing pollutants, to assess the bioavailability of xenobiotics in two reaches of a large lotic system in Southeast Brazil: a less disturbed area (site 1) in the upper stretch, and an area in the middle stretch, which receives various industrial and agricultural effluents from upstream cities (site 2). In addition, G. brasiliensis were exposed to a single dose of 50 mg kg-1 beta-naphthoflavone (BNF) or of 50 mg kg-1 dimethylbenzoanthracene (DMBA) to test the effects on, respectively, the hepatic EROD activity in S9 supernatant fraction, and the frequency of micronucleated erythrocytes three days after the i.p. treatments, and compared to an unexposed group, to test its potential as a sentinel for biomonitoring studies. The EROD activity was approximately two-fold higher in fish from the impacted stretches than in fish from the less disturbed stretches (p < 0.05). Micronuclei (MN) frequency was also significantly different (p < 0.01) in DMBA-treated fish. The induced EROD activity in the impacted site suggests that organochlorinated pollutants are reaching the biota of the Paraíba do Sul River, confirming the suitability of Geophagus brasiliensis as a useful sentinel species to detect changes caused by xenobiotics(AU)

Assuntos

RESUMO

The bluefish, Pomatomus saltatrix (Linneus 1766) is captured by industrial, artisanal, and recreational fisheries throughout its distribution range. The reproductive biology of P. saltatrix in the southwestern Atlantic was studied using 1,102 specimens captured by the Brazilian commercial fleet between March 2014 and December 2015. The recruitment period was identified from records of juveniles in experimental beach seine hauls carried out on sandy beaches in the external sector of Guanabara Bay for four years (2012-2015). Based on the reproductive indices and on the macro- and microscopic analyses of the gonads, spawning peaks were identified in autumn and spring. The size at first maturity was estimated at 35.5, 38.3, and 37.4 cm for females, males, and general, respectively. Ovary analyses and measurements of the oocyte diameters indicated that bluefish are multiple spawners with asynchronous oocyte development. The batch fecundity estimate was 202,752.5 eggs and ranged from 9,800.9 to 426,787.0 eggs. The species reproduces throughout the entire study area, but it is more active in the south of Arraial do Cabo. The young-of-the-year were recorded on shallow water in all seasons, with modal peaks in the summer months. The parameters estimated in this study expand and update information on this species, providing important data for the evaluation and fisheries management of the stock of P. saltatrix in the southwestern Atlantic.(AU)

Assuntos

RESUMO

The bluefish, Pomatomus saltatrix (Linneus 1766) is captured by industrial, artisanal, and recreational fisheries throughout its distribution range. The reproductive biology of P. saltatrix in the southwestern Atlantic was studied using 1,102 specimens captured by the Brazilian commercial fleet between March 2014 and December 2015. The recruitment period was identified from records of juveniles in experimental beach seine hauls carried out on sandy beaches in the external sector of Guanabara Bay for four years (2012-2015). Based on the reproductive indices and on the macro- and microscopic analyses of the gonads, spawning peaks were identified in autumn and spring. The size at first maturity was estimated at 35.5, 38.3, and 37.4 cm for females, males, and general, respectively. Ovary analyses and measurements of the oocyte diameters indicated that bluefish are multiple spawners with asynchronous oocyte development. The batch fecundity estimate was 202,752.5 eggs and ranged from 9,800.9 to 426,787.0 eggs. The species reproduces throughout the entire study area, but it is more active in the south of Arraial do Cabo. The young-of-the-year were recorded on shallow water in all seasons, with modal peaks in the summer months. The parameters estimated in this study expand and update information on this species, providing important data for the evaluation and fisheries management of the stock of P. saltatrix in the southwestern Atlantic.

Assuntos

RESUMO

ABSTRACT The bluefish, Pomatomus saltatrix (Linneus 1766) is captured by industrial, artisanal, and recreational fisheries throughout its distribution range. The reproductive biology of P. saltatrix in the southwestern Atlantic was studied using 1,102 specimens captured by the Brazilian commercial fleet between March 2014 and December 2015. The recruitment period was identified from records of juveniles in experimental beach seine hauls carried out on sandy beaches in the external sector of Guanabara Bay for four years (2012-2015). Based on the reproductive indices and on the macro- and microscopic analyses of the gonads, spawning peaks were identified in autumn and spring. The size at first maturity was estimated at 35.5, 38.3, and 37.4 cm for females, males, and general, respectively. Ovary analyses and measurements of the oocyte diameters indicated that bluefish are multiple spawners with asynchronous oocyte development. The batch fecundity estimate was 202,752.5 eggs and ranged from 9,800.9 to 426,787.0 eggs. The species reproduces throughout the entire study area, but it is more active in the south of Arraial do Cabo. The young-of-the-year were recorded on shallow water in all seasons, with modal peaks in the summer months. The parameters estimated in this study expand and update information on this species, providing important data for the evaluation and fisheries management of the stock of P. saltatrix in the southwestern Atlantic.

RESUMO

The white mouth croaker Micropogonias furnieri is the most common species of Sciaenidae in Guanabara Bay, southeastern coast of Brazil. Data from monthly trawls taken from a shrimp boat between May 2003 and June 2005 showed that white mouth croakers are regularly present year round; the catch was entirely composed of juveniles. The length-weight relationship for pooled sexes was represented by the equation Wt = 0.0053*Lt 3.183. Significant seasonal differences in the condition factor were not observed (p>0.05). Regarding the morphometric characterization of this population stratum, most of the characters examined showed isometric growth, except for Pre-anal Distance, which showed positive allometry, and Eye Diameter, which showed negative allometry. Morphometric aspects of the population in Guanabara Bay seem to be similar to those from coastal populations of southeastern Brazil (population I), which differ from populations on the southern coast.

A corvina, Micropogonias furnieri, é a espécie de Sciaenidae mais comum na baía de Guanabara, sudeste do Brasil. Com base em arrastos mensais efetuados por um barco camaroneiro que opera com rede simples de arrasto-de-fundo, entre maio de 2003 e junho de 2005 observou-se que sua presença é regular ao longo de todo o ano, sendo capturados apenas juvenis. A relação comprimento-peso para os sexos grupados é representada pela equação Pt = 0,0053*Ct 3,183. Não foram constatadas diferenças sazonais significativas (p>0,05) para o fator de condição, indicando que este não sofre amplas variações ao longo do ano. Com relação à caracterização morfométrica do estrato populacional que utiliza a baía e é capturado pelos arrasteiros, observa-se que a maioria dos caracteres examinados apresenta crescimento isométrico, exceto para a Distância Pré-anal, que apresentou alometria positiva, e o Diâmetro do Olho, com alometria negativa. A população da baía de Guanabara parece ser similar em seus aspectos morfométricos às outras populações costeiras da região sudeste do Brasil (população I), que diferem das populações da costa Sul.

RESUMO

The white mouth croaker Micropogonias furnieri is the most common species of Sciaenidae in Guanabara Bay, southeastern coast of Brazil. Data from monthly trawls taken from a shrimp boat between May 2003 and June 2005 showed that white mouth croakers are regularly present year round; the catch was entirely composed of juveniles. The length-weight relationship for pooled sexes was represented by the equation Wt = 0.0053*Lt 3.183. Significant seasonal differences in the condition factor were not observed (p>0.05). Regarding the morphometric characterization of this population stratum, most of the characters examined showed isometric growth, except for Pre-anal Distance, which showed positive allometry, and Eye Diameter, which showed negative allometry. Morphometric aspects of the population in Guanabara Bay seem to be similar to those from coastal populations of southeastern Brazil (population I), which differ from populations on the southern coast.

A corvina, Micropogonias furnieri, é a espécie de Sciaenidae mais comum na baía de Guanabara, sudeste do Brasil. Com base em arrastos mensais efetuados por um barco camaroneiro que opera com rede simples de arrasto-de-fundo, entre maio de 2003 e junho de 2005 observou-se que sua presença é regular ao longo de todo o ano, sendo capturados apenas juvenis. A relação comprimento-peso para os sexos grupados é representada pela equação Pt = 0,0053*Ct 3,183. Não foram constatadas diferenças sazonais significativas (p>0,05) para o fator de condição, indicando que este não sofre amplas variações ao longo do ano. Com relação à caracterização morfométrica do estrato populacional que utiliza a baía e é capturado pelos arrasteiros, observa-se que a maioria dos caracteres examinados apresenta crescimento isométrico, exceto para a Distância Pré-anal, que apresentou alometria positiva, e o Diâmetro do Olho, com alometria negativa. A população da baía de Guanabara parece ser similar em seus aspectos morfométricos às outras populações costeiras da região sudeste do Brasil (população I), que diferem das populações da costa Sul.